TedJ
Well-Known Member
- Joined
- December 4, 2006
- Messages
- 875
- Reaction score
- 25
- City, State
- NY
- Year, Model & Trim Level
- '94 Sport
You need to take a step back and stop loading the parts cannon with bigger and bigger items. Tossing an entire harness at it is going to be a hell of a lot of work and may not even fix the problem or create new ones.
The first thing I would check is your ground integrity. It looks like you have original cables with replacement terminals, which is a bad sign for the overall cable condition. It is very common for the cables to corrode internally, especially near the terminal and near the frame ground. The negative battery terminal has two parts to it. One is a fat cable that goes to the frame and then the engine block. The other goes to a two pin connector, which is extremely important. One of the pins in that connector carries all the grounds for the PCM and many sensors. There is a ground from the PCM to the body as well (located right near the PCM), and very strange things happen if there is a bad ground connection in this system. You can use a high current test light and your meter to do voltage drop testing of all of these grounds to the battery negative post.
I attached some schematics that should help. With the PCM and sensors unplugged, you can also use some probes and a test light to check each wire for the ability to carry current and check for shorts to power/ground/other circuits. Hopefully you got good quality sensors but it cannot hurt to check for any shorts from the heater to sensor wires in the sensor as well.
The first thing I would check is your ground integrity. It looks like you have original cables with replacement terminals, which is a bad sign for the overall cable condition. It is very common for the cables to corrode internally, especially near the terminal and near the frame ground. The negative battery terminal has two parts to it. One is a fat cable that goes to the frame and then the engine block. The other goes to a two pin connector, which is extremely important. One of the pins in that connector carries all the grounds for the PCM and many sensors. There is a ground from the PCM to the body as well (located right near the PCM), and very strange things happen if there is a bad ground connection in this system. You can use a high current test light and your meter to do voltage drop testing of all of these grounds to the battery negative post.
I attached some schematics that should help. With the PCM and sensors unplugged, you can also use some probes and a test light to check each wire for the ability to carry current and check for shorts to power/ground/other circuits. Hopefully you got good quality sensors but it cannot hurt to check for any shorts from the heater to sensor wires in the sensor as well.